821280964 has 81 divisors (see below), whose sum is σ = 1767603117. Its totient is φ = 332891328.

The previous prime is 821280959. The next prime is 821280989. The reversal of 821280964 is 469082128.

The square root of 821280964 is 28658.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 157703364 + 663577600 = 12558^2 + 25760^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 9227832 + ... + 9227920.

Almost surely, 2^821280964 is an apocalyptic number.

821280964 is the 28658-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821280964

821280964 is an abundant number, since it is smaller than the sum of its proper divisors (946322153).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821280964 is a wasteful number, since it uses less digits than its factorization.

821280964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242 (or 121 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 40.

The cubic root of 821280964 is about 936.4772948017.

The spelling of 821280964 in words is "eight hundred twenty-one million, two hundred eighty thousand, nine hundred sixty-four".